[whatwg] Parsing: how to deal with marker while reconstructing the active formatting elements?

The section 12.2.3.3 The list of active formatting elements 
(https://html.spec.whatwg.org/multipage/syntax.html#the-list-of-active-formatting-elements) 
has steps to "reconstruct the active formatting elements". The steps include

Step 6: "If entry is neither a marker nor an element that is also in the 
stack of open elements, go to the step labeled rewind."

Step 7: "Advance: Let entry be the element one later than entry in the 
list of active formatting elements."

Step 8: "Create: Insert an HTML element for the token for which the 
element entry was created, to obtain new element."


How to deal with the case where the `entry` points to a marker after 
step 7? Obviously one cannot create a marker as an HTML element.

This case seems possible because only the Step 6 checks for a marker and 
then Step 7 blindly advances the list and may set `entry` to a marker.


(I'm asking this question because I hit this case while parsing user 
input with html5lib PHP implementation and that implemenetation crashes 
while trying to create an HTML element from marker.)

-- 
Mikko

Received on Wednesday, 8 April 2015 05:55:51 UTC